Fix nightly pipeline (#9368)

* Add stage for publishing-gate

* Allow publishing-gate to run when populating cache

Author: sarahchen6

.gitlab-ci.yml

@@ -950,12 +950,13 @@ verify_maven_central_deployment:
       done
 
 publishing-gate:
+  stage: publish
   needs:
     - job: verify_maven_central_deployment
-      optional: true
+      optional: true # Required for releases only
   rules:
     - if: '$POPULATE_CACHE'
-      when: never
+      when: on_success
     - if: '$CI_COMMIT_TAG =~ /^v[0-9]+\.[0-9]+\.[0-9]+$/'
       when: on_success
     - when: manual